1. Technical Field
The present invention relates to hard disks and to processes for fabrication of hard disk drive and, more particularly, to an acceptance tester for testing the acceptance of a hard disk drive that has passed through a series of fabrication processes, and a method of fabricating the hard disk drive using the acceptance tester.
2. Related Art
Hard disk drives, which are widely used as auxiliary memory devices in a computer system, pass through a series of fabrication processes. Exemplars that are representative of recent efforts in the art include particular construction of hard disk drives and fabrication and testing, such as U.S. Pat. No. 5,654,841 to Hobson et al., entitled Detection Of Mechanical Defects In A Disc Drive Using Injected Test Signals, U.S. Pat. No. 5,424,638 to Huber, entitled Sampled Data Flaw Detection For Magnetic Media, U.S. Pat. No. 5,210,860 to Pfeffer et al., entitled Intelligent Disk Array Controller, U.S. Pat. No. 5,166,936 to Ewert et al., entitled Automatic Hard Disk Bad Sector Remapping, U.S. Pat. No. 5,047,874 to Yomtoubian, entitled Technique For Certifying Disk Recording Surface, U.S. Pat. No. 4,152,695 to Democrate et al., entitled Method Of Writing Infornation Relating To Faults In A Magnetic Recording Medium, and U.S. Pat. No. 3,710,235 to Barrager et al., entitled Method And Apparatus For Testing Batch Fabricated Magnetic Heads During Manufacture Utilizing A Magnetic Field Generated By A Current Carrying Conductor.
Some of these efforts (see, for example, Hobson et al. '841 and Barrager et al. '235) disclose methods and apparatus for testing for mechanical defects in a disk drive during the manufacturing process. These methods and apparatus, however, involve the application of electrical current or signals to the magnetic media in combination with complicated and expensive hardware arrangements for analyzing the results and detecting flaws in the manufacture of the product. Other patents listed above (for example, see Ewert et al. '936) disclose methods and arrangements for detecting flaws in magnetic media well after the manufacturing process is completed (for example, during use of the product by a user).
In other conventional fabrication processes for a hard disk drive, the acceptance of each hard disk drive set is finally tested using only pass or fail data in accordance with a final test program. Accordingly, if an Hard disk drive set having defects is judged as having passed the test due to an error in the final test system or due to an operator's error, the Hard disk drive set having defects is not able to be detected in any following process step, resulting in production of a poor hard disk drive set.